Manufacture of aromatic nitriles and aldehydes



United States Patent 3,325,504 MANUFACTURE OF AROMATIC NITRILES AND ALDEHYDES Robert K. Grasselli, Garfield Heights, Ohio, assignor to The Standard Oil Company, Cleveland, Ohio, 2 corporation of Ohio No Drawing; Filed Apr. 23, 1965, Ser. No. 450,537 Claims. (Cl. 260-2943) The present invention relates to a process for the manufacture of monoolefinically unsaturated aromatic nitriles and aldehydes from certain substitute-d allyl aromatic compounds. More particularly, it relates to a direct process for converting compounds having the structure wherein A is an aromatic radical such as phenyl, naphthyl, pyridyl, quinolyl, anthryl or phenanthryl and R is either hydrogen or a hydrocarbon group having from 1 to 10 carbon atoms, to monoolefinically unsaturated aldehydes by catalytic reaction with molecular oxygen or to monoolefinically unsaturated nitriles by catalytic reaction with molecular oxygen and ammonia. For example, allyl benzene may be converted to cinnamaldehyde or to cinnamonitrile with high yields.

In the past, processes for the preparation of cinnamaldehyde or cinnamonitrile have generally involved several steps and usually produced relatively low yields of rather impure products. More recently a direct, one-step catalytic process has been discovered wherein ,B-methyl styrene is converted to cinnamaldehyde or cinnamonitrile and this process is more fully described and claimed in the copending U.S. patent application of R. K. Grasselli and I. L. Callahan, Ser. No. 423,818, filed Jan. 6, 1965. The reaction in this recently discovered process is comparatively straightforward and the yields are fair. Surprisingly, the reaction of the instant process starting with the substituted allyl aromatic compound, though it apparently involves an electronic rearrangement, gives exceptionally good yields.

It is an object of'this invention to produce directly from an allyl aromatic compound such as allyl benzene the aldehyde and nitrile compounds such as cinnamaldehyde and cinnamonitrile. This may be accomplished, for example, by reacting allyl benzene with a reactant such as (1) oxygen and (2) oxygen and ammonia, in the presence of any one of several oxidation catalysts, and preferably a catalyst comprising antimony oxide as an essential ingredient in combination with at least one other polyvalent metal oxide, hereinafter more fully disclosed.

Several catalysts have been found to be operative in the process of this invention. In general, the oxides of one or more polyvalent metal elements are useful as catalysts in the process of this invention. More particularly, the useful catalysts for this process are those composed of at least one oxide of an element appearing in Groups I-B, II-B, IV-A, V, VI-B, VII-B and VIII of the Mendelyeev Periodic Table (see Handbook of Chemistry and Physics, 38th ed., Chemical Rubber Publishing Co., Cleveland, Ohio, pp. 394-395). Operative catalysts inclu-de the combined oxides of antimony and at least one other polyvalent metal such as the combined oxides of antimony and uranium, the combined oxides of antimony and iron, the combined oxides of antimony and manganese, the combined oxides of antimony and thorium, the combined oxides of antimony and cerium and the combined oxides of antimony and tin and mixtures of one or more of the foregoing combinations of oxides.

Other catalysts useful in this invention are composed of at least one salt of molybdic, phosphomolybdic, tungstic and phosphotungstic acids with an element appearing in Groups I-B, II-B, IV-A, V, VI-B, VII-B and VIII of the Mendelyeev Periodic Table. Operative catalysts include bismuth molybdate, bismuth phosphomolybdate, antimony-bismuth molybdate, antimony-bismuth phoS- phomolybdate, bismuth phosphotungstate, bismuth silicomolybdate, bismuth silicophosphomolybdate, bismuth silicotungstate, bismuth silicophosphotungstate and mixtures of one or more of the foregoing combinations of salts.

Promoter metal oxides incorporated in the catalyst so as to comprise up to 15% by weight thereof, based on the weights of the elemental metals, may be used effectively, but amounts up to 5% by weight of one or more promoter oxides are preferred.

The catalyst useful in the present invention may be used alone or supported on or impregnated in a carrier material. Any suitable carrier material may be used, including silica, alumina, thoria, zirconia, titania, boron phosphate, silicon carbide, pumice, diatomaceous earth, clay and the like. In general, the support will be employed in amounts less than by weight of the final catalyst composition.

The catalysts useful in the present invention may be prepared in numerous ways known in the art. For instance, the catalyst may be manufactured by co-g elling the various ingredients and drying or by spray-drying, extruding or spherulizing in oil.

The catalyst may be calcined to produce desirable physical properties such as attrition resistance, surface area and particle size. It is preferred that the calcined catalyst be further heat-treated in the presence of oxygen at an elevated temperature above 500 F. but below a temperature deleterious to the catalyst. For the purpose of the present invention, a catalyst having a particle size between 1 and 500 microns and a surface area in the range from 1 to 25 square meters per gram is preferred.

In the process for the manufacture of monoolefinically unsaturated aromatic nitriles and aldehyde-s embodied herein, the temperature may be any temperature in the range from 200 to 800 C., the preferred range being 350 to 500 C.

The pressure at which the instant reaction is conducted is an important variable; a preferred pressure for conducting the reaction is from about 1 to 3 atmospheres so that the yield of undesirable by-products is minimized.

The apparent contact time employed in the process of this invention should be kept within certain limits to obtain good selectivity and yields. The apparent contact time may be defined as the time in seconds a unit volume of gas, measured at reactor conditions of temperature and pressure, is in contact with the apparent unit volume of catalyst. It may be calculated, for instance, from the apparent volume of the catalyst bed, the average temperature and pressure of the reactor and the mass flow rate of the reaction mixture. The optimum contact time will depend upon the particular 'alkyl substituted aromatic hydrocarbons being oxidized or ammoxidized. A contact time from 0.01 to 50 seconds may be used, though a contact time of 0.1 to 5 seconds is preferred.

Molar ratios of air to the vinyl substituted aromatic hydrocarbon may vary from approximately 1:5 to 1:200. Ratios near the high limit make for poor selectivity, while ratios near the low limit decrease catalyst activity. Preferred molar ratios of air to hydrocarbon are in the range of 1:15 to 1:100.

No ammonia is present in the feed when the vinyl substituted aromatic is to be oxidized to the corresponding aldehyde, but only when the ammoxidation reaction producing the nitrile is to be conducted. In this latter case, up to 20 moles of ammonia per mole of hydrocarbon are found to be effective. For economic reasons, approximatelystoichiometri'c quantities. of hydrocarbon feed and ammonia are preferred.

.Any molecular oxygen containing gas can be used in this process. Oxygen itself may be used without any diluent, although it is usually desirable to use in addition to oxygen at least one diluent such as steam, carbon dioxide, nitrogen and the inert gases. Any molar ratio of diluent Within the range of 1:1 to 1:100 may be used, but the range from 1:50 to 1275 gives satisfactory control of the reaction in either a fixed bed or fluidized bed reatcor.

The equipment required for the reaction may be the standard type used for carrying out vapor phase oxidation reactions, such equipment being well-known to those skilled in the art. For the experimental work in the present invention, a tubular bed reactor, equipped with an injection system was irrunersed in a molten salt bath. The gaseous reactants and diluents were introduced from pressurized containers fitted with pressure regulators, and the amount introduced was measured by the flow meters.

The reactants are introduced into the reactor either at reaction temperature by first passing them through a preheater zone or by introducing them directly into the reactor and allowing them to come to reaction temperature as they travel through the catalyst bed.

The reaction products can be recovered by any desirable method. One method is the use of solvent scrubbers. A preferred method is the use of one or more Dry Ice traps in series which serve to isolate the reaction products by condensing them. The products of reaction were analyzed using standary techniques including gas chromatography,

infrared analysis and nuclear magnetic resonance.

While only the preferred form of the invention is described in detail, it will be apparent to those skilled in the art that various modifications may be made therein without departing from the scope of the invention or the scope of the appended claims.

In the examples the following definitions are employed:

Percent Conversion-carbon basis= weight of carbon in the products of reaction weight of carbon in the propylene feed The combined oxides of the polyvalent metals are referred to as the active phase of the catalyst'and the silica carrier is referred to as the inactive phase. The weight percent of promoter metals referred to in the following.

examples corresponds to the ratio of the actual weight of the elemental metal present in the oxide or salt mixed into the unpromoted catalyst to the total weight of active phase, including the promoter metal oxide.

Examples 1-12 322.8 gm. of Sb O (White Star Grade M) and 136.2 gm. of U 0 Grade 1 were mixed with 800 cc. of concentrated nitric acid and heated for minutes until fuming ceased. To this was added some water to cool the slurry, and 655.7 gm. of a 30% by weight colloidal suspension of silica in water and sufficient ammonia hydroxide to obtain a pH of 8. The-catalyst was filtered and washed with water, dried overnight at 120 C., calcined for 24 hours at 800 F. and heat-treated for 8 hours at 672' gm. were mixed with 373.3 gm. of a 30% by weight colloidal suspension of silica in Water, in a high speed blender, and the mixture was extruded onto aluminum foil. This material was dried overnight at 120 C. and heat-treated for 6 hours at 1725 F.

Examples 1315 Runs made with an antimony oxide-uranium oxide catalyst, set forth in Table 11 below, show conversions for the oxidation of allylbenzene to cinnamaldehyde at different temperatures, and for comparison, the conversion 45 of fi-methyl-styrene to cinnamaldehyde at 460 C.

TABLE I Mole Ratio Per Pass Conversion tol i r d o t 1 t Ting)" a a S 0 6e 3 Feed NH; Air N Cinnam- Benzo- Atropo- Quinonitrile nitrile nitrile oline 1 Allylbenzene 60(70Sb/30U)40(S102) 460 1 1.5 72.5 57.8 4.6 2 fl-methylsty- (70Sb/30U)40(Si01) 460 1 1.5 50 72.5 18.6 17.7

rene. 3 Allylbenzene 60(70Sb/30U)40(S10z) 410 1 1.5 50 72.5 46.7 3.2 4 B-rnethylsty- 75(95Sb/5FQ)25(S102)... 460 1 1.5 50 72.5 5.1 14.4

tone. 5 Allylbenzenm- 75(95Sb/5F6)25(Sl0z) 410 v1 1.5 50 72. 5 18.8 8.3 6 d0 50(Bi IMo12O5z)50(SiO2) 410 1 1.5 50 72.5 5.1 4.6 44(Sb6.lBi5JP1VlO1105fi.2)+56(Sl02) 460 1 3.0 48. 5 42. 5 6. 7 9. 6 44(Sbu'l3i5,iPMoizossa) 6(SiO2) 410 1 O 5 5 6 6 44(Sbu BiriPMomosm)+56(Si02) 410 1 1. 5 50 72. 5 11.7 3. 7 62BizO3-38MOO3 460 1 1. 5 50 72. 5 9. 6 15. 6 82.5(Niio,sFGBiPMOiz sMs)+l7.5(si0 360 1 1. 5 50 72. 5 14. 0 5.0 12 d0. 82.5(Ni10.5FeSb0.5Bl0,5M0l2055)+1 -5(Si02) 360 1 1.5 50 72.5 7.5 3.2

TABLE II Mole Ratio Per Pass Conversion to- Expt. Temp,

No. Feed Catalyst C. 7

Feed NHa Air N2 Cmuam- Benz- Atropaldehyde aldehyde aldehyde 13 Allylbenzenenus. 60(70Sb/30U)40(Si0) 460 1 51.5 72.5 32.8 8.3 14...". 0.- fiO(Sb/30U)4O (SiO-2) 410 1 0 51.5 72.5 24.5 1.2 15 B-methylstyrenmfl 60(70Sb/30U)40(Si0z) 460 1 51.5 72.5 6.6 5.7

5 I claim: 1. A process for the manufacture of a compound having the structure R H A(|1=(IJ-CN wherein A is an aromatic group selected from the group consisting of phenyl, naphthyl, pyridyl, quinolyl, anthryl and phenanthryl radicals and R is selected from the group consisting of hydrogen and a lower alkyl group having from 1 to 4 carbon atoms, comprising reacting a monoolefinically substituted aromatic compound having the structure Wherein A and R have the same connotation as above, With reactants comprising ammonia and molecular oxygen in the presence of the oxide of at least one metal element selected from the group consisting of antimony, uranium, iron, manganese, thorium, cerium, tin, or in the presence of at least one salt of molybdic, phosphomolybdic, tungstic and phosphotungstic acids with at least one of the said metal elements, supported or unsupported by a catalyst support at about 1 to 3 atmospheres pressure at a temperature in the range of 200 to 800 C.

2. The process of claim 1 in which the monoolefinically substituted aromatic compound is allyl benzene.

3. The process of claim 1 in which the monoolefinically substituted aromatic compound is allyl pyridine.

4. The process of claim 1 in which the molar ratio of allyl benzene to air in the range from 1:5 to 1:200 and the molar ratio of allyl benzene to ammonia is in the range of 1:01 to 1:5.

5. The process of claim 1 in which the operating pressure is at about atmospheric pressure.

6. The process of claim 5 in which the operating temperature is in the range of 350 to 500 C.

7. The process of claim 6 in which the catalyst is a fixed bed, pelletized catalyst.

8. The process of claim '6 in which the catalyst is a fluidized bed, spherulized catalyst.

9. The process of claim 7 in which the apparent con tact time is in the range of 0.1 to 15 seconds.

10. The process of claim 8 in which the apparent contact time is in the range of 0.1 to 15 seconds.

No references cited.

WALTER A. MODANCE, Primary Examiner.

ALAN L. ROTMAN, Assistant Examiner. 

1. A PROCESS FOR THE MANUFACTURE OF A COMPOUND HAVING THE STRUCTURE 